Electric furnace and process of heating substances uniformly and at a controllable temperature.



E. F. VON WILMOWSKY, DEGD.

E. J. PRINDLE. EXEQUTOR. CTRIG FURNACE AND PROCESS OF HEATING SUBSTANUES UNIFORMLY AND AT A CONTROLLABLE TEMPERATURE.

APPLICATION TILED APR. 18,1914. 1,]. 28,64Q Patented Feb. 16, 1915.

ERR/tummy UNITED STATES PATENT OFFICE. I

ERWIN F. VON WIIilUIO WSKY, DECEASED, LATE OF BOSTON, MASSACHUSETTS, BY EDWIN J. PRINDLE, EXECUTOR, OF EAST ORANGE, JERSEY, ASSIGNOR TO NORSK HYDRO-ELEKTRISK KVAELSTOFAKTIESELSKAB, A CORPORATION OF NORWAY.

ELECTRIC FURNACE AND PROCESS OF HEATING SUBSTANCES UNIFORMLY AND AT A CONTROLLABLE TEMPERATURE.

Specification of Letters Patent.

Original.application'filed October 28, 18 96, Serial No. 610,286. Divided and this application filed April 18 v 1914. Serial No. 832,932.

T aflcwhom it may concern.

Be it known that ERWIN F. VON WILMOW- SKY, late a citizen of theUnited States of- America and resident of Boston, county of Suffolk, Commonwealth of Massachusetts, did invent certain new and useful Improvements in Electric Furnaces and Processes of Heating Substances Uniformly and at a Controllable Temperature, of which the following is aspecification.

pThepresent application is a division of .original application Serial No. 6l0,286,-filed' October 28, 1896, and includes subject matter erased without prejudice from said original application with the express intention of applying for a separate patent.

This invention relates in general to the treatment of substances electrically, and more particularly to the treatment of gases.

The inventor has found that an arc-furnace in which the materialsto be heated are brought directly into the arc and exposed the means and process hereinafter described.

The invention consists therefore in the novel means "and process hereinafter set forth and illustrated in the drawings.

Apparatus for carrying the process into effect is illustrated in the accompanying drawings, and this, as well as the process which is thereby carried out, will be described hereinafter.

In the drawings, Figure 1 is a central longitudinal section of a furnace and its electrical and mechanical connections and- '.-accessories; Fig. 2 is adiagrammatic view of a modificat on thereof, certain of the elecal -and mechanical connections being tied. ,7 "f fer-ring to the drawings, A(, A A and only slightly magnetic material chosen to or made to resist a high temperature, preferably carbon with a few per cent. of carbidskin it, such as is used for electrolytic wor a (1 are radially arranged hollow carbon rods cemented into the respective tubes A,

movedforward and backward and serves to strike an arc in starting the furnace.

B is a central electrode extending within and through the tube electrodes A, A A and A, between which tube electrodes and central electrode the arc is struck by pencils a 7 a is a shell of fire-brick orloose magnesia, outside of which is an external iron casing a -cis a solenoid surrounding the reaction chamber within the furnace and is separated from the external casing a by an asbestos layer a.

The solenoid c, when continuous or single-phase alternating, currents are used, is connected in series with the arc-current and in parallel with a rheostat, so that the magnetism may be regulated independently of the arc-current. When two-phase currents are used, one phase for the arc and the other phase for the solenoid, the rheostat is put in series with the solenoid. The former of these arrangements of circuits is. illustrated in Fig. 1, where 9 represents a separately excited generator of either. the direct current or single-phasealternating type, and z i the rheostat.

The reaction chamber of the furnace is provided with a condui t d of refractory material for the gases to be treated, and a Patented Feb. 16, 1915.

closely fitting into closed circuit of this conduit is completed -by pipe d. In a part of this circuit, such as pipe d, is provided a fan d of refractory material with cooled axle bearings and driven from the outside. Through one of two openings, (2 d, provided in the inclosure of said circuit, new gas or vapor is added in continuous stream, while through the other opening on the oppositeside of the circuit a corresponding volume of gases or vapors escapes. The fan can be dispensed with when it is found sufii cient that the particles of the gas or vapor pass the series of disks only once.

To start the furnace, the rods of cylinder A are pressed against rod B and at the same time current connection is made between these rods and the lower end of rod B, and then an arc is established by withdrawing the rods of oylinderA as described more fully in Patent 1,094,354, dated April 26, 1914, granted to Erwin'F. von Wilmowsky; Edwin J. Erindle, executor. Thereupon by withdrawingthe rods ofcylinder A? and severing said connection of ,these rifdswith the lower end of rod B, anothei 'arc is established at the level of p the rods of cylinder A while the pressure of the dynamo is increased at the same time by more than fifty volts, according to the tubes or cylinders. tinguished repeatedly until the temperature distance between the central rod B and the These arcs will be ex is high. in this way a series of disks is gradually established between concentric cylindrical surfaces, through which disks the charge is moved.

The disks can be formed according to the desired temperature of a vastly different current-density. If they are intended to be of very low temperature comparatively,

and the central carbon rod of a furnace n tended for gases has '6. g. one-half (a) inch! diameter, the carbon tube inside one and lone-half (1%) inches diameter, the area between the rod and the tube being therefore one and six-tenths (1.6) square inches, then an energy supply of about fifteen (15) amperes and forty-five volts continuous current in a magnetic field of 150 ampereturns will give already a perfect luminous disk, while with alternating current about sixty (60) volts and fifty-five (55) amperes are needed, with 4:00 ampere-turns for the solenoid. These figures depend upon the preparation of the carbon and above all upon the temperature existing already in the furnace;

the central electrode. This furnace can be started without carbon rods by moving. B toward B until it touches, and withdrawing and producing an are at first between B". and B. tance increases and the current at last refers to use the insulated outside tube as part 'of its way, two disks are formed between 13 and the tube, and between the tube and B And at last two or more disks are established in the same wayby moving B, between B and the tube and between the tube and B It is clear from what "has been said, how to arrange for a larger number of disks, when such larger number is desired. v

In the operation of these furnaces, after the arc has been started, the effect of the solenoid is first to'cause the arc to rotate. Should the arc be extinguished, the solenoid current is weakened and the are again started. As soon as the furnace has reached a high temperature, a moreor less regularly Thereafter when the electrode-di srotating arc is seen, he. a luminous, more or less spiral broad line, org'li'nes, between some rotating, brightly incandescent spots on the electrodes. This rotating arc avoids overheating to a certain extent, but is for most purposes not a sufficient solution of,

the problem mentioned in the preamble.

The magnetism, and at the same time the 1 voltage of the mam current, are now increased untilthe rotating arc is transformed into a homogeneous luminous disk, hereinbefore referred to as the arc-disk or the 1 disk. -Thereby the highest temperature existing in the furnace is reduced considerably, though the supply of energy is in-n creased, the heat being now uniform. The

electric discharge in this form is perfectly steady and controllable. A homogeneous luminous disk stretches itself across the tube, making on the two electrodes rings of entirely uniform and moderate brightness.

No rotation whatever is visible, and the electricity appears to stream simultaneously between said rings, not preferring at any one moment a special linear path. This disk, when only a few inches in diameter, is

noiseless, except with alternating current,

which besides requires, in order to form a disk, more amperes and more volts for the same apparatus. When the diskis once formed, any increase in current will ihcrease the luminosity and'the temperature, which" latter can be regulated with precision by' regulating the current-supply. When the central-electrode is moved even considerably out of its central position the disk is not changed thereby in its appearance or uniform luminosity, and nomotion in it is visible. When the magnetism is sustained and the current for'the diskreduced, the disk is changed at last into a quick rotating arc emitting a roaring noise, even if less than IAI two inches in diameter. This is another striking difference between the disk and the rotatingtarc. i The simultaneous streamin of, electricity mentioned above makes this rnace particularly fit to pass therethrough gases or vapors which are to be exposed to electrolytic and electro-synthetic forces or to be heated to a certain temperature favorable to a desired reaction; The feeding tube may be located adjacent the outlet tube so that the heat from the outcoming stream of gases is communicated to the fresh gas mixture. This maybe done by dividin the feeding tube c shown in the 'origina application above mentioned for treatment of solid materials, this tube being stationary instead of rotating.

G111 the following claims the word arcdisk .will be used in place of what in the above specification is called simply disk, the word arc designating any electrical discharge through a gas or vapor-space which is made conductive by heat, whatever its character and appearance may be. I claim p 1. The process of treating mixed gases, comprising passing them repeatedly in contact with an electric arc.

2. In an electric furnace, the combination of a heating chamber, means for forming'an arc therein, and means for causing gases to l pass repeatedly through the heating chamer. a n 7 3: In combination, a furnace chamber in whlch reactions are caused to take place, means for producing an electric arc in said .rality of electric arcs influenced by said chamber, a conduit circuit-including said chamber, means to cause a circulation of gas through said circuit, and gas supply and gas outlet connections for said circuit.

4. In combination, a furnace chamber m .which reactions are caused to take place,

means to form an arc-disk in said chamber,

a conduit-circuit including said chamber,

sides of said, arc. I

5. In combination, means; producing etic field, means for] producing an Q peatedlycirculatin gas through said field I and in contact wit said are.

6. In combination, means for producing a magnetic field, means for produclng a and means for repeatedly circulating a gas past and in contact with said arcs.

7. Incombination, means tfor producing a magnetic field, means for producing a plurality of electric arcs in series'influenced by said field, and means for repeatedly circu- 1 lating a gas past and in contact with said arcs.

EDWIN J. PRINDLE,

means for causing the movement of gases within said circuit, and supply and outlet; connections for said circuit' 'j 'on opposite}; I

Ewecutor of the estate of Erwin F. can We'l mowsky.

Witnesses:

L. BRODERIOK, vV. G. LLOYD. 

